The present invention relates to a thumbturn assembly for use with a single cylinder deadbolt lock, and method of assembly. More particularly, the present invention is a thumbturn assembly and method which allows for forged brass trim, concealed mounting screws, easy installation, and aesthetic appeal.
Deadbolt lock mechanisms for doors normally include an operating handle either in the form of a knob or of a thumbturn. A user rotates the thumbturn using a thumb and finger placed on opposite sides of a central bar portion of the thumbturn. In a conventional single cylinder deadbolt lock mechanism, an oscillating crank actuates a bolt which selectively engages a strike plate on a door frame within which the door is closed. The crank is provided with a thumbturn extending from one side of the door for operating the bolt. The thumbturn is mounted for rotation in a plate or rose body secured to the door panel. The rotation of the thumbturn is required to extend or retract the deadbolt latch into or out of a faceplate guide assembly that is installed in a clearance hole. This is accomplished by coupling the thumbturn to the deadbolt latch using a driver bar or other linkage. Therefore, a mechanical link is created so that when the thumbturn is rotated, the driver bar acts to operate the movement of the deadbolt latch.
The typical thumbturn is made by forming a somewhat yieldable planar sheet of metallic material into an approximately elliptical central portion having a pair of tabs extending from the opposite sides of the central portion. The central portion is then drawn into a cup, leaving the tabs in their original planar position. The tabs are then curved into semi-cylindrical shape facing in the same direction. Finally the tabs are moved into a position concentric with an axis normal to the original plane. The ends of the tabs are notched forming lugs. The tabs of the thumbturn are inserted into the hub of the rose body. A cap is placed over the end of the hub. The cap has apertures through which the lugs are inserted and extend through. The thumbturn is rotatably secured to the rose body by bending, or splaying the lugs, thereby forcing the cap against the hub and forcing the bottom of the thumbturn against the bearing ring of the rose body.
There are several problems associated with these type of thumbturn assemblies. One problem is that the lugs can become loose causing rattling and potentially allowing the thumbturn to disconnect from the rose body. Another problem is the durability, or structural strength of the thumbturn which is generally made from a yieldable sheet of metallic material. Still another problem is that the thumbturn must be formed in a series of bending and forming steps which add to the cost and cycle time of the manufacturing process.
Therefore, there remains a need in the art for a thumbturn assembly that can be satisfactorily secured within a rose body housing over an extended period of time without becoming loose or rattling. There also remains a need in the art for a high strength thumbturn assembly that can be manufactured easily and economically and provide for simple installation.
The present invention solves the problems encountered by the prior art by securely coupling the thumbturn assembly to the inside housing of the deadbolt in a unique a and novel manner which extends the life and durability of the thumbturn assembly.
The present invention is a deadbolt thumbturn assembly for attachment to an inside housing of the deadbolt assembly. The deadbolt thumbturn assembly comprises a thumbturn, a bushing collar, and a rose body. The bushing collar is rotatably attached to an extension portion of the thumbturn. The rose body includes an aperture wherein the bushing collar is rotatably attached to the rose body. Finally, the bushing collar is fixably attached to the inside housing of the deadbolt assembly such that rotation of the thumbturn actuates and deactuates the deadbolt assembly. The method of attaching a thumbturn assembly to a deadbolt assembly of the present invention comprises the steps of inserting an extension of a thumbturn into a collar bushing and attaching them together such that the thumbturn extension is able to rotate within the collar. The collar bushing is then inserted into an aperture of a rose body and attached thereto such that the collar bushing is able to rotate within the rose body aperture to form a deadbolt thumbturn assembly. Finally, the collar bushing is fixably attached to a non-rotating portion of the deadbolt assembly so that rotation of the thumbturn actuates and deactuates the deadbolt.